Channel reservation method in wireless network and communication equipment

Abstract

The invention provides a channel reservation method in a wireless network and communication equipment, which are used for data communication between an AP (access point) and one or more STAs (station), are also suitable for communication between APs (access points) and communication between STAs, adopt a flexible channel reservation mechanism, can reserve the time or backoff value of one or more transmission opportunities in the future, and improve the communication efficiency. The reservation mode has the characteristics of real-time performance and flexibility, so that channel access conflicts among the nodes are reduced, and the service quality requirements of low-delay and high-reliability services are further ensured.

Description

Technical Field

[0001] The present invention relates to the field of communications, and in particular to a communication reservation method and communication equipment thereof. Background Art

[0002] WLAN is a general term for wireless networks covering a local area, with Wi-Fi being a typical example. WLAN has attracted widespread attention from industry and academia due to its high transmission rate, low cost, and open use. WLAN operates in unlicensed spectrum. Its most famous and dominant international standard is IEEE802.11. Since the first version was released in 1997, IEEE 802.11 has evolved into major standard evolution versions such as 802.11, 802.11a and 802.11b, 802.11g, 802.1n, 802.11ac, and 802.11ax (regarded as the sixth generation of Wi-Fi, namely Wi-Fi 6). The latest generation of WLAN standard IEEE 802.11be (regarded as the seventh generation of Wi-Fi, namely Wi-Fi 7) will be officially released in 2024 or 2025. The next generation WLAN standard IEEE 802.11bn (regarded as the eighth generation of Wi-Fi, or Wi-Fi8) has also begun research and is scheduled to be released in 2028. WLAN carries more than 50% of the world's Internet Protocol (IP) traffic and has become the main wireless network at present and in the future together with cellular networks.

[0003] WLAN has a variety of network structures, and the most commonly used structures are described as follows: Figure 1 As shown. WLAN consists of one or more Basic Service Sets (BSS). The concept of BSS is close to the concept of cell, and BSS and cell will be used interchangeably in the following text. Each BSS is generally composed of a wireless access point (Access Point, AP) and one or more non-AP stations (non-AP Station, referred to as non-AP STA for short). For example, wireless access points are generally implemented in wireless routers, and non-AP STAs are generally implemented in terminal devices such as smart phones. Generally speaking, all uplink services are sent by non-STA STA to AP, and all downlink services are sent by AP to non-AP STA. Stations located in the same BSS are called this BSS or this cell, and stations located in different BSSs are called external BSSs or external cells. An AP in the same BSS as any non-AP STA is called the associated AP of the non-AP STA, and the non-AP STA is called the associated STA of the AP.

[0004] Non-AP STAs are allowed to communicate with each other, which is called point-to-point (P2P). Stations include both APs and non-AP STAs.

[0005] The physical layer packet transmitted by the station (AP or non-AP STA) over the air interface is called the Physical Layer Protocol Data Unit (PPDU). PPDU is the packet sent by each node to the air interface through the physical layer. PPDU can be understood as an air interface data packet. PPDU includes a preamble and a payload. The preamble or payload of the PPDU may contain a Network Allocation Vector (NAV). NAV is a time length indicating the remaining time length that the sending station of the PPDU still needs to continue to occupy the channel from the end time of the PPDU.

[0006] When any station receives a PPDU, if it is determined that the PPDU comes from this BSS (i.e., this cell), and the end time of the NAV it carries exceeds the end time of the intra-BSS NAV of this cell currently recorded by the station, it is necessary to update the intra-BSS NAV of this cell so that the end time of the intra-BSS NAV of this cell is consistent with the end time of the NAV carried in the received PPDU.

[0007] When any site receives a PPDU, if it is determined that the PPDU comes from an external BSS (i.e., an external cell) and the end time of the NAV it carries exceeds the end time of the basic NAV (basic NAV) currently recorded by the site, it is necessary to update the basic NAV (basic NAV) so that the end time of the basic NAV (basic NAV) is consistent with the end time of the NAV carried in the received PPDU.

[0008] Channel access refers to the process by which nodes in the network obtain the right to use a channel. Since WLAN operates in an unlicensed spectrum, this means that various wireless systems can use this spectrum resource openly and free of charge, so contention-based channel access is required. Specifically, IEEE 802.11 stipulates that nodes in WLAN use the Carrier Sense Multiple Access with Collision Avoid (CSMA / CA) mechanism. The CSMA / CA mechanism uses the Listen Before Talk (LBT) method to access the channel, that is, if a node wants to obtain the right to use the channel to interact with frames, it first needs to listen to the busyness of the channel. Only when the channel is idle and meets certain rules can it obtain the right to use the channel.

[0009] At present, more and more wireless network applications and services have put forward more stringent requirements on latency characteristics and transmission reliability, such as online games, virtual reality, medical treatment, industrial sites, etc. Therefore, the next generation of wireless networks will ensure latency performance and transmission reliability as key technical goals, which has been widely valued by the industry.

[0010] like Figure 2 As shown in the figure, restricted target wakeup time (r-TWT) is a new mechanism for ensuring low-latency services derived from the existing broadcast TWT (Broadcast TWT) of IEEE 802.11ax.

[0011] Under the 802.11be standard, non-AP EHT STA (hereinafter referred to as EHT STA) has many real-time applications, and the traffic of these applications has very strict latency requirements. Based on this, the r-TWT mechanism is proposed, which states that the AP broadcasts one or more r-TWT service periods (SP) through beacon frames or probe response frames. When the EHT STA in the BSS receives any r-TWT SP information broadcast by the AP, if the dot11RestrictedTWTOptionImplemented of the STA is set to true, then the EHT STA must end its transmission opportunity (TXOP) before the start time of the r-TWT SP. In addition, the AP can set a quiet interval (Quiet Interval) aligned with the start time of the r-TWT SP in the beacon (Beacon) or (ProbeResponse) frame, with a duration of TU (Time Uint), sometimes also called 1 millisecond (ms), 1TU = 1024 microseconds (us). The EHT STA belonging to this r-TWT SP group (grouped by Broadcast TWT ID) is required to ignore the above quiet interval and then compete for the channel after the r-TWT SP starts. The EHT STA that does not belong to the r-TWT SP group (grouped by Broadcast TWT ID) can ignore or not ignore the above quiet interval; other STAs need to remain silent according to the quiet interval, which will reduce the number of STAs competing for the channel in the BSS and increase the probability of EHT STAs with low-latency services getting the channel.

[0012] The r-TWT information is indicated in the TWT element field. The TWT element structure is as follows: Figure 3As shown. For a broadcast TWT, the TWT parameter information contains multiple broadcast TWT parameter sets. The broadcast TWT recommendation subfield (Broadcast TWT Recommendation) in the request type field (RequestType) of each broadcast TWT parameter set is used to indicate the TWT type specified by the broadcast TWT parameter set. Its value is 4, indicating that this broadcast TWT parameter set corresponds to an r-TWT. This request type is introduced by IEEE 802.11be, so the legacy STA cannot understand it. If a broadcast TWT parameter set corresponds to an r-TWT, then the broadcast TWT information subfield (Broadcast TWT Info) in the TWT element field contains a one-bit r-TWT service information subfield existence indication subfield (Restricted TWT Traffic Info Present). The value of this bit is 1, indicating that the TWT element field contains the r-TWT service information subfield (Restricted TWT TrafficInfo) shown in the figure, and 0, indicating that the TWT element field does not contain the r-TWT service information subfield (Restricted TWTTraffic Info) shown in the figure. The r-TWT Traffic Info subfield (Restricted TWT Traffic Info) is used by non-AP STA and AP to negotiate uplink / downlink r-TWT TID and non-rTWT TID. The Broadcast TWT ID subfield indicates the identification number of the TWT group.

[0013] The r-TWT mechanism allows the AP to reserve channel access resources for some STAs in advance, so that these STAs have higher channel access priority in the r-TWTSP phase, but there are the following problems:

[0014] 1) The r-TWT mechanism requires interaction between the AP and the STA, and requires the AP to send Beacon frames for indication, which is complex and costly, and it is difficult to support temporary or real-time reservations.

[0015] 2) APs and STAs in other cells will not parse the r-TWT information indicated in the Beacon sent by this cell. Therefore, in a multi-cell scenario, the channel access priority of r-TWT is difficult to guarantee. Summary of the invention

[0016] In order to overcome the deficiencies of the prior art, the present invention provides a channel reservation method and communication equipment in a wireless network.

[0017] The technical solution adopted by the present invention to solve its technical problem is:

[0018] The present invention is for data communication between an AP and one or more STAs, and is also applicable to communication between APs and between STAs. A station includes an AP or a non-AP STA.

[0019] A channel reservation method in a wireless network, in which an AP or a STA in a WLAN reserves the start time of the next or next TXOPs in a sent PPDU, such as Figure 5 As shown, the specific steps are:

[0020] Step 1: The first station sends a first PPDU, which carries channel reservation information. The channel reservation information indicates the start time of a future TXOP, or the start time of multiple future TXOPs. The start time of a future TXOP or the start time of multiple future TXOPs are both called the reservation time. The reservation time is the start time of the next TXOP or the start time of multiple consecutive TXOPs, or is not the start time of the next TXOP or the start time of multiple consecutive TXOPs.

[0021] The channel reservation information is carried in a MAC frame carried by the first PPDU, or in a preamble of the first PPDU;

[0022] If the channel reservation information is carried in the MAC frame, the implementation step is to carry it in the A-Control field in the IEEE 802.11 standard, wherein the Control ID field adopts a value reserved in the IEEE 802.11 standard, and the value indicates that the A-Control field identifies the channel reservation information;

[0023] The first implementation of the Control Information field is that the value of the Control Information field represents the time interval between the start time of a future TXOP and the end time of the first PPDU transmission;

[0024] In the second implementation of the control information field, the control information field includes two subfields, the first subfield is the time granularity field, the value of which indicates the time granularity, and the second subfield is the duration indication field, the value of which is combined with the time granularity field to indicate the time interval between the start time of a future TXOP and the end time of the first PPDU transmission, that is, the duration is equal to the value of the second field multiplied by the time granularity indicated by the first field;

[0025] The third implementation of the control information field is to indicate the start time of multiple TXOPs that follow in the future; first, the control information field includes a reservation number field, which indicates the number of reservations N, and a duration indication field is followed by the reservation number field, which is used to indicate the time interval between the start time of the next N TXOPs and the start time of the previous TXOP; wherein, the start time of the first TXOP that follows in the future is the time after the transmission end time of the first PPDU has passed the time interval;

[0026] The fourth implementation of the control information field is to indicate the start time of multiple future TXOPs; first, the control information field includes a time granularity field, the value of which is the same as that of the second implementation, and the time granularity field is followed by multiple duration indication fields, and the value of each duration indication field and the time granularity field determines the start time of a future TXOP, that is, the duration is equal to the value of the second field multiplied by the time granularity indicated by the first field; therefore, multiple duration indication fields indicate the start time of multiple future TXOPs; each duration indication field includes a value, and if the time granularity field of the fourth implementation does not exist, then the start time of each future TXOP is directly corresponded by each duration indication field, and the corresponding method is the same as the effect of the third implementation;

[0027] If the channel reservation information is carried in the preamble of the first PPDU, the position of the channel reservation information in the preamble of the first PPDU is not restricted;

[0028] Step 2: The second station successfully receives the first PPDU and successfully parses the channel reservation information carried in the first PPDU. The second station records the start time of one or more future TXOPs of the first station indicated by the channel reservation information. The second station calls the start time of one or more future TXOPs of the first station indicated by the channel reservation information as the reserved time.

[0029] Step 3: The second station ends its own transmission opportunity (TXOP) before each scheduled time, and the second station backs off to 0 before each scheduled time. However, if it is found that the transmission end time of the proposed TXOP is later than the scheduled time, the second station abandons the current transmission and regenerates a backoff value without updating the contention window (CW).

[0030] Step 4: When the first station arrives at each of its own scheduled times, it determines whether to send a PPDU according to the judgment rules; the judgment rules are as follows, and the PPDU can be determined to be sent if one of them is met:

[0031] 4.1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately;

[0032] 4.2) If NAV is 0 and the carrier sense is continuously idle for a short period of time from the scheduled time, the PPDU is sent immediately; the short period of time is not limited and can be SIFS or PIFS;

[0033] 4.3) If normal backoff is successful, PPDU is sent immediately;

[0034] The second station is not allowed to compete for the channel within a period of time starting from each reserved time, and the time period is not limited.

[0035] A channel reservation method in a wireless network, the specific steps are:

[0036] Step 1: The first station sends a first control frame to the third station. The first control frame carries reservation information, indicating the start time of one or more future TXOPs of the first station.

[0037] Step 2: When the third station receives the first control frame, it replies with a response frame of the first control frame, or carries the reservation information in the first control frame in the response frame to indicate the start time of one or more future TXOPs of the first station;

[0038] Step 3: After receiving the first control frame or the second control frame, the second station different from the third station successfully parses the channel reservation information carried in the first control frame or the response frame of the first control frame; the second station ends its own transmission opportunity before each reserved time; and the second station backs off to 0 before each reserved time, but finds that the end time of the TXOP transmission to be initiated is later than the reserved time, then the second station abandons this transmission and regenerates a backoff value without updating the contention window;

[0039] Step 4: When the first station arrives at each of its own scheduled times, it determines whether to send a PPDU according to the judgment rules; the judgment rules are as follows, and the PPDU can be determined to be sent if one of them is met:

[0040] 4.1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately;

[0041] 4.2) If NAV is 0 and the carrier sense is continuously idle for a short period of time from the scheduled time, the PPDU is sent immediately; the short period of time is not limited and can be SIFS or PIFS;

[0042] 4.3) If normal backoff is successful, PPDU is sent immediately;

[0043] The second station is not allowed to compete for the channel within a period of time starting from each reserved time, and the time period is not limited.

[0044] The first control frame and the response frame of the first control frame are TWT request and response frames of IEEE 802.11, or r-TWT request and response frames.

[0045] A channel reservation method in a wireless network, in which an AP or STA in a WLAN reserves a backoff value for the next or next several channel accesses in a sent PPDU. First, each station maintains a "reserved backoff value table", which indicates whether the channel is reserved by other stations from the current moment. In the reserved backoff value table, the value of the i-th element is 1, indicating that the i-1th time slot in the future is reserved by other stations; the value of 0 indicates that the i-1th time slot in the future is not reserved by other stations. The values ​​and meanings are opposite, or other storage structures or value methods are used, as long as it can be distinguished whether the i-th time slot in the future is reserved by other stations. The current moment is recorded as the 0th time slot, and the time slot refers to:

[0046] 1) The TXOP time period of the TXOP holder;

[0047] 2) Physical carrier sensing or virtual carrier sensing determines that the channel is busy until the channel changes from busy to idle for a period of DIFS or AIFS;

[0048] 3) Physical carrier sensing or virtual carrier sensing determines that the channel is idle and a backoff time slot has passed. Each station deletes the frontmost element in the "reserved backoff value table" every time a time slot has passed, representing that a time slot has passed;

[0049] The specific steps are:

[0050] Step 1: The first station sends a first PPDU, which carries channel reservation information; the channel reservation information is a backoff value immediately following the next channel access, the backoff value of the next channel access represents the backoff value of the next multiple channel accesses, and the backoff value of the next or subsequent multiple channel accesses is called a reservation backoff value;

[0051] The channel reservation information is carried in a MAC frame carried by the first PPDU, or in a preamble of the first PPDU;

[0052] If the channel reservation information is carried in the MAC frame, the first implementation method is to carry it in the A-Control field in the IEEE 802.11 standard, where the control identifier field uses a value reserved in the IEEE 802.11 standard, and the value indicates that the A-Control field identifies the channel reservation information;

[0053] The first implementation of the control information field is that the value of the control information field directly represents the backoff value of a future channel access;

[0054] The second implementation of the control information field indicates the backoff value of multiple channel accesses in the future. First, the control information field includes a reservation number field, the reservation number field value is the reservation number N, and the reservation number field is followed by a backoff value field, and the backoff value field indicates the backoff value of the next N channel accesses in the future.

[0055] The third implementation of the control information field indicates the backoff values ​​of multiple channel accesses in the future, including multiple backoff value fields. The value of the i-th backoff value field determines the backoff value of the i-th channel access in the future. The value of the i-th backoff value field is m, and m≥0, which means that the backoff value of the i-th channel access in the future is m. Each backoff value field contains a value, which means that the backoff value of the i-th channel access in the future is not specified.

[0056] If the channel reservation information is carried in the preamble of the first PPDU, the position of the channel reservation information in the preamble of the first PPDU is not restricted;

[0057] The backoff value reserved by the first station cannot be a backoff value with a value of 1 in the "reserved backoff value table"; the first backoff time slot of the i-th backoff of the first station is the next time slot of the i-1th channel access success time slot of the first station;

[0058] Step 2: The second station successfully receives the first PPDU and successfully parses the channel reservation information carried in the first PPDU;

[0059] Assume that the channel reservation information represents the backoff value of the first station's N future channel accesses, recorded as o1, o2...oN; the time slot corresponding to the backoff value of the first station's N future channel accesses is filled with 1 in the corresponding position of the "reserved backoff value table" of the second station; specifically, the value of the element o1+1, o1+o2+1,...o1+o2+...+oN+1 in the "reserved backoff value table" of the second station is 1;

[0060] Step 3: When the first station reaches its reserved backoff value, if there is a packet transmission, one of the decision rules is used to determine whether the PPDU can be sent; the decision rules are as follows, and any one of them is sufficient:

[0061] 3.1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately;

[0062] 3.2) When the backoff value reserved by the first station reaches its own, if there is no packet transmission, it sends a frame to indicate that there is no packet transmission. For example, the frame is a QoS Null frame in IEEE 802.11, or an NDP frame.

[0063] A channel reservation method in a wireless network, in which an AP and a non-AP STA in a WLAN exchange channel reservation capabilities and configure channel reservation enabling parameters, comprises the following specific steps:

[0064] Step 1: The first non-AP STA sends a first management frame to the first AP, where the first management frame indicates whether the first non-AP STA has the channel reservation capability; the first management frame is a probe request frame, an association request frame, or a reassociation request frame.

[0065] Step 2: The first AP sends a second management frame to the first non-AP STA, where the second management frame indicates whether the AP has the channel reservation capability; the second management frame is a beacon frame, a probe response frame, an association response frame, or a reassociation response frame.

[0066] The second management frame contains 0, 1 or more of the following information:

[0067] Channel reservation enable information, indicating whether channel reservation is enabled; a value of 1 indicates that the channel reservation function is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function is enabled, and a value of 2 indicates that the channel reservation function is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function is enabled, and a value of 2 indicates that the channel reservation function is enabled, and a value of 3 indicates that the channel reservation functions described in Example 1 and Example 2 are enabled at the same time, and a value of 0 indicates that the channel reservation function is disabled.

[0068] The present invention also provides a communication device, comprising a unit or module for executing the reservation method as described above.

[0069] The present invention provides a computer-readable storage medium, wherein program instructions are stored in the computer-readable storage medium. When the program instructions are executed on a computer, the computer is enabled to execute the method described above.

[0070] The beneficial effect of the present invention is that it adopts a flexible channel reservation mechanism, which can reserve the time or backoff value of one or more future transmission opportunities. Such a reservation method has the characteristics of real-time and flexibility, thereby reducing channel access conflicts between nodes, and further ensuring the service quality requirements of low-latency and high-reliability services. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 This is the network structure of WLAN.

[0072] Figure 2 It is a schematic diagram of the prior art.

[0073] Figure 3 Schematic diagram of the related frame structure of prior art 1.

[0074] Figure 4 System architecture or scenario diagram.

[0075] Figure 5 Embodiment 1 Figure, Figure 5 (a) Schematic diagram of indicating the start time of a future TXOP in PPDU, (b) Schematic diagram of indicating the start time of multiple future TXOPs in PPDU, (c) Reservation information indication diagram based on A-Control.

[0076] Figure 6 Implementation diagram of embodiment 2.

[0077] Figure 7 This is a diagram of Example 2. Figure 7 (a) Schematic diagram of the backoff value indicating a future channel access in the PPDU, Figure 7 (b) is a schematic diagram of the backoff value indicating multiple channel accesses in the future in the PPDU. Figure 7 (c) is a reservation information indication diagram based on A-Control.

[0078] Figure 8 The reserved backoff value indicates the intention. DETAILED DESCRIPTION

[0079] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0080] Embodiment 1

[0081] Embodiment 1 is that in a WLAN, an AP or a STA reserves the start time of the next or next TXOPs in a sent PPDU. Moment, such as Figure 6 shown.

[0082] The steps of embodiment 1 are:

[0083] Step 1: The first station sends a first PPDU, wherein the first PPDU carries channel reservation information, and the channel reservation information indicates the start time of a future TXOP. Figure 5 (a), or indicates the start time of multiple TXOPs in the future, such as Figure 5 As shown in (b), the start time of the future one or more TXOPs is called the reservation time, and the reservation time is the start time of the next or the next consecutive TXOPs, or is not the start time of the next or the next consecutive TXOPs;

[0084] The channel reservation information is carried in a MAC frame carried by the first PPDU, or in a preamble of the first PPDU;

[0085] If the channel reservation information is carried in a MAC frame, one implementation method is to carry it in the A-Control field in the existing IEEE 802.11 standard, such as Figure 5 (c) shown; wherein the control identification (Control ID) field adopts a value reserved in the existing IEEE 802.11 standard, for example, one of the values ​​9 to 14, which indicates that the A-Control (A-Control) field identifies the channel reservation information.

[0086] The first implementation method of the control information field is that the value of the control information field directly represents the time interval between the start time of a future TXOP and the end time of the first PPDU transmission. The correspondence between the value and the time interval is not limited. For example, if the value of the control information field is 1900, it represents 1900us.

[0087] In the second implementation of the control information field, the control information field includes two subfields. The first subfield is the time granularity field, and the value is used to indicate the time granularity. For example, different values ​​represent 1us, 512us or 1024us. The second subfield is the duration indication field, and the value is combined with the time granularity field to determine the time interval between the start time of a future TXOP and the end time of the first PPDU transmission. That is, the duration is equal to the value of the second field multiplied by the time granularity represented by the first field. For example, the value of the duration indication field is 20, and the value of the time granularity field indicates 1ms. Then the time interval between the start time of a future TXOP and the end time of the first PPDU transmission is 20×1ms=20ms.

[0088] The third implementation method of the control information field is to indicate the start time of multiple TXOPs that follow in the future; first, the control information field includes a reservation number field, which indicates the number of reservations N, and the reservation number field is followed by a duration indication field, which is used to indicate the time interval between the start time of the next N TXOPs and the start time of the previous TXOP; wherein, the start time of the first TXOP that follows in the future is the time after the time interval after the end of the transmission of the first PPDU.

[0089] The fourth implementation of the control information field is the start time of multiple future TXOPs; first, the control information field includes a time granularity field, and the value meaning is the same as the second implementation method. The time granularity field is followed by multiple duration indication fields. The values ​​of each duration indication field and the time granularity field determine the start time of a future TXOP, that is, the duration is equal to the value of the second field multiplied by the time granularity represented by the first field. For example, the duration indication field has a value of 20, and the time granularity field value indicates 1ms, then the time interval between the start time of a future TXOP and the end time of the first PPDU transmission is 20×1ms=20ms; therefore, multiple duration indication fields represent the start time of multiple future TXOPs; each duration indication field contains a special value, such as a value of 0 or all 1s in binary, indicating that the duration indication field is invalid; if the time granularity field of the fourth implementation method does not exist, then the start time of each future TXOP is directly corresponded by each duration indication field, and the corresponding method is the same as the effect of the third implementation method.

[0090] If the channel reservation information is carried in the preamble of the first PPDU, the position of the channel reservation information in the preamble of the first PPDU is not limited, for example, the channel reservation information may be carried in the UHR-SIG field;

[0091] Step 2: The second station successfully receives the first PPDU and successfully parses the channel reservation information carried in the first PPDU. The second station records the start time of one or more future TXOPs of the first station indicated by the channel reservation information. The second station calls the start time of one or more future TXOPs of the first station indicated by the channel reservation information as the reserved time.

[0092] Step 3: The second station ends its own transmission opportunity (TXOP) before each scheduled time, and the second station backs off to 0 before each scheduled time. However, if it is found that the transmission end time of the proposed TXOP is later than the scheduled time, the second station abandons the current transmission and regenerates a backoff value without updating the contention window (CW).

[0093] Step 4: When the first station arrives at each of its own scheduled times, it determines whether to send a PPDU according to the judgment rules; the judgment rules are as follows, and the PPDU can be determined to be sent if one of them is met:

[0094] 4.1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately;

[0095] 4.2) If NAV is 0 and the carrier sense is continuously idle for a short period of time from the scheduled time, the PPDU is sent immediately; the short period of time is not limited and can be SIFS or PIFS;

[0096] 4.3) If normal backoff is successful, PPDU is sent immediately;

[0097] The second station is not allowed to contend for the channel within a period of time starting from each reserved time. The present invention does not limit the time period, for example, it can be 1024us, or DIFS duration.

[0098] In addition to the above-mentioned method, there is another implementation method of the first embodiment, which is to carry the reservation information in the control frame through the interaction of the control frame. Figure 6 As shown:

[0099] Step 1: The first station sends a first control frame to the third station. The first control frame carries reservation information and represents the start time of one or more future TXOPs of the first station.

[0100] Step 2: When the third station receives the first control frame, it replies with a response frame of the first control frame, or the response frame carries the reservation information in the first control frame, which is used to represent the start time of one or more future TXOPs of the first station;

[0101] Step 3: After receiving the first control frame or the second control frame, the second station different from the third station successfully parses the channel reservation information carried in the first control frame and / or the response frame of the first control frame; the second station ends its own transmission opportunity before each reserved time; and the second station backs off to 0 before each reserved time, but finds that the end time of the TXOP transmission to be initiated is later than the reserved time, then the second station abandons this transmission and regenerates a backoff value without updating the contention window;

[0102] Step 4: When the first station arrives at each of its own scheduled times, it determines whether to send a PPDU according to the judgment rules; the judgment rules are as follows, and the PPDU can be determined to be sent if one of them is met:

[0103] 4.1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately;

[0104] 4.2) If NAV is 0 and the carrier sense is continuously idle for a short period of time from the scheduled time, the PPDU is sent immediately; the short period of time is not limited and can be SIFS or PIFS;

[0105] 4.3) If normal backoff is successful, PPDU is sent immediately;

[0106] The second station is not allowed to contend for the channel within a period of time starting from each reserved time. The present invention does not limit the time period, for example, it can be 1024us, or DIFS duration.

[0107] The first control frame and the response frame of the first control frame are TWT request and response frames of IEEE 802.11, or r-TWT request and response frames.

[0108] Embodiment 2 describes how an AP or STA in a WLAN reserves the next or next few channel accesses in the PPDU sent. The backoff value. Figure 7 As shown:

[0109] The steps of the second embodiment are:

[0110] First, each station maintains a "reserved backoff value table" that indicates whether the channel has been reserved by other stations from the current moment. Figure 8 As shown, the value of the i-th element is 1, indicating that the i-1th time slot in the future is reserved by other sites; the value of 0 indicates that the i-1th time slot in the future is not reserved by other sites. The values ​​and meanings are opposite, or other storage structures or value methods are used, as long as it can be distinguished whether the i-th time slot in the future is reserved by other sites. The current moment is recorded as the 0th time slot. The concept of time slot here refers to:

[0111] 1) The TXOP time period of the TXOP holder;

[0112] 2) Physical carrier sensing or virtual carrier sensing determines that the channel is busy until the channel changes from busy to idle for a period of DIFS or AIFS;

[0113] 3) Physical carrier sensing or virtual carrier sensing determines that the channel is idle and a backoff time slot (9us) has passed. Each station deletes the frontmost element in the "reserved backoff value table" every time a time slot has passed, representing a time slot has passed;

[0114] Step 1: The first station sends a first PPDU, which carries channel reservation information; the channel reservation information is a backoff value immediately following the next channel access, such as Figure 7 (a), the latter represents the backoff value for the next multiple channel accesses, such as Figure 7 As shown in (b), the backoff value for the next or subsequent channel access is called the reservation backoff value;

[0115] The channel reservation information is carried in a MAC frame carried by the first PPDU, or in a preamble of the first PPDU;

[0116] If the channel reservation information is carried in the MAC frame, the first implementation method is to carry it in the A-Control field modified in the IEEE 802.11 standard, such as Figure 7 (c), wherein the control identification field adopts a value reserved in the existing standard, for example, one of the values ​​9 to 14, which indicates that the A-Control field identifies the channel reservation information;

[0117] The first implementation manner of the control information field is that the value of the control information field directly represents the backoff value of a future channel access.

[0118] The second implementation of the control information field represents the backoff value of multiple channel accesses in the future; first, the control information field includes a reservation number field, the reservation number field is set to the reservation number N, and the reservation number field is followed by a backoff value field, and the backoff value field is used to represent the backoff value of the next N channel accesses in the future;

[0119] The third implementation of the control information field indicates the backoff value of multiple channel accesses in the future, including multiple backoff value fields. The value of the i-th backoff value field determines the backoff value of the i-th channel access in the future. The value of the i-th backoff value field is m (m≥0), which means that the backoff value of the i-th channel access in the future is m. Each backoff value field contains a special value, such as all 1s in binary, indicating that the backoff value of the i-th channel access in the future is not specified.

[0120] If the channel reservation information is carried in the preamble of the first PPDU, the position of the channel reservation information in the preamble of the first PPDU is not limited, for example, the channel reservation information is carried in the UHR-SIG field.

[0121] It should be noted that the backoff value reserved by the first station cannot be a backoff value with a value of 1 in the "reserved backoff value table"; the first backoff time slot of the i-th backoff of the first station is the next time slot of the i-1th channel access success time slot of the first station;

[0122] Step 2: The second station successfully receives the first PPDU and successfully parses the channel reservation information carried in the first PPDU;

[0123] Assume that the channel reservation information represents the backoff value of the first station for the next N channel accesses, recorded as o1, o2, ... N ; Fill the time slot corresponding to the backoff value of the first station's future N channel accesses with 1 in the corresponding position of the "reserved backoff value table" of the second station; specifically, fill the o1+1, o1+o2+1, ... o1+o2+...+o in the "reserved backoff value table" of the second station with 1; N The value of the element with +1 is 1;

[0124] Step 3: When the first station reaches its reserved backoff value, if there is a packet transmission, one of the decision rules is used to determine whether the PPDU can be sent; the decision rules are as follows, and any one of them is sufficient:

[0125] 3.1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately;

[0126] 3.2) When the backoff value reserved by the first station reaches its own, if there is no packet transmission, it sends a frame to indicate that there is no packet transmission. For example, the frame is a QoS Null frame in IEEE 802.11, or an NDP frame.

[0127] Embodiment 3 is to exchange channel reservation capability and configure channel reservation between AP and non-AP STA in WLAN Enable parameter.

[0128] The steps of embodiment 3 are as follows:

[0129] Step 1: The first non-AP STA sends a first management frame to the first AP, where the first management frame indicates whether the first non-AP STA has a channel reservation capability; for example, the first management frame is a Probe Request frame, an Association Request frame, or a Reassociation Request frame;

[0130] Step 2: The first AP sends a second management frame to the first non-AP STA, where the second management frame indicates whether the AP has a channel reservation capability; for example, the second management frame is a beacon frame, a probe response frame, an association response frame, or a reassociation response frame.

[0131] The second management frame contains 0, 1 or more of the following information:

[0132] Channel reservation enabling information indicates whether channel reservation is enabled; for example, a value of 1 indicates that the channel reservation function described in Example 1 is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function described in Example 2 is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function described in Example 1 is enabled, and a value of 2 indicates that the channel reservation function described in Example 2 is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function of Example 2 or Example 3 is enabled, and a value of 2 indicates that the channel reservation function described in Example 4 is enabled, and a value of 3 indicates that the channel reservation functions described in Example 1 and Example 2 are enabled at the same time, and a value of 0 indicates that the channel reservation function is disabled. The corresponding relationship between the above values ​​and meanings is only an example, as long as there is a one-to-one correspondence.

[0133] The maximum time interval between the start time of a future TXOP and the end time of the first PPDU transmission in the first embodiment.

[0134] The maximum value of the backoff value for the next or next several channel accesses in the second embodiment.

[0135] The maximum number of reservations in Embodiment 1 or Embodiment 2.

[0136] Embodiment 3 is a negotiation between nodes on whether to adopt embodiment 1 or embodiment 2, as well as the corresponding parameters. Therefore, embodiment 3 is an auxiliary embodiment 1 and 2, and is not a replacement for the former. In other words, embodiment 3 + embodiment 1 can work, and embodiment 3 + embodiment 2 can work. Of course, without embodiment 3, the former can also work alone.

[0137] The beneficial effect of the present invention is that it adopts a flexible channel reservation mechanism, which can reserve the time or backoff value of one or more future transmission opportunities. Such a reservation method has the characteristics of real-time and flexibility, thereby reducing channel access conflicts between nodes, and further ensuring the service quality requirements of low-latency and high-reliability services.

Claims

1. A method for channel reservation in a wireless network, characterized in that The steps include: Step 1: The first station sends a first PPDU, which carries channel reservation information. The channel reservation information indicates a start time of a future TXOP of the first station, or a start time of multiple future TXOPs of the first station. The start time of a future TXOP or the start time of multiple future TXOPs are both called reservation time. The reservation time is the start time of the next or consecutive multiple TXOPs, or is not the start time of the next or consecutive multiple TXOPs. The channel reservation information is carried in a MAC frame carried by the first PPDU, or in a preamble of the first PPDU; If the channel reservation information is carried in the MAC frame, the first implementation step is to carry it in the A control field in the IEEE 802.11 standard, wherein the control identification field adopts a value reserved in the IEEE 802.11 standard, and the value indicates that the A control field identifies the channel reservation information; A first implementation of the control information field is that the value of the control information field represents the time interval between the start time of a future TXOP of the first station and the end time of the first PPDU transmission; In a second implementation of the control information field, the control information field includes two subfields, the first subfield is a time granularity field, the value of which indicates the time granularity, and the second subfield is a duration indication field, the value of which is combined with the time granularity field to indicate the time interval between the start time of a future TXOP of the first station and the end time of the first PPDU transmission, that is, the duration is equal to the value of the second field multiplied by the time granularity indicated by the first field; A third implementation of the control information field is to indicate the start time of multiple TXOPs immediately following the first station in the future; first, the control information field includes a reservation number field, the reservation number field indicates the number of reservations N, and the reservation number field is followed by a duration indication field, which is used to indicate the time interval between the start time of the immediately following N TXOPs in the future and the start time of the previous TXOP; wherein the start time of the first TXOP immediately following in the future is the time after the transmission end time of the first PPDU is elapsed; The fourth implementation of the control information field is to indicate the start time of multiple future TXOPs; first, the control information field includes a time granularity field, the value of which is the same as that of the second implementation, and the time granularity field is followed by multiple duration indication fields, and the value of each duration indication field and the time granularity field determines the start time of a future TXOP, that is, the duration is equal to the value of the second field multiplied by the time granularity indicated by the first field; therefore, multiple duration indication fields indicate the start time of multiple future TXOPs; each duration indication field includes a value, and if the time granularity field of the fourth implementation does not exist, then the start time of each future TXOP is directly corresponded by each duration indication field, and the corresponding method is the same as the effect of the third implementation; If the channel reservation information is carried in the preamble of the first PPDU, the position of the channel reservation information in the preamble of the first PPDU is not restricted; Step 2: The second station successfully receives the first PPDU and successfully parses the channel reservation information carried in the first PPDU. The second station records the start time of one or more future TXOPs of the first station indicated by the channel reservation information. The second station calls the start time of one or more future TXOPs of the first station indicated by the channel reservation information as the reserved time. Step 3: The second station ends its own transmission opportunity before each scheduled time, and the second station backs off to 0 before each scheduled time. However, if it is found that the end time of the TXOP transmission to be initiated is later than the scheduled time, the second station abandons this transmission and regenerates a backoff value without updating the contention window. Step 4: When each of the first station's scheduled times arrives, the first station determines whether to send a PPDU according to the decision rule; The second station is not allowed to compete for the channel within a period of time starting from each reserved time, and the time period is not limited.

2. A method for channel reservation in a wireless network, characterized in that The steps include: Step 1: The first station sends a first control frame to the third station, where the first control frame carries reservation information and indicates the start time of the TXOP of one or more first stations in the future of the first station; Step 2: When the third station receives the first control frame, it replies with a response frame of the first control frame, or carries the reservation information in the first control frame in the response frame to indicate the start time of one or more future TXOPs of the first station; Step 3: After receiving the first control frame or the second control frame, the second station different from the third station successfully parses the channel reservation information carried in the first control frame or the response frame of the first control frame; The second station ends its own transmission opportunity before each scheduled time; Furthermore, the second station backs off to 0 before each scheduled time, but if it is found that the end time of the TXOP transmission to be initiated is later than the scheduled time, the second station abandons the current transmission and regenerates a backoff value without updating the contention window; Step 4: When each of the first station's scheduled times arrives, the first station determines whether to send a PPDU according to the decision rule; The second station is not allowed to compete for the channel during a period starting from each reserved time, and the time period is not limited; The first control frame and the response frame of the first control frame are TWT request and response frames of IEEE 802.11, or r-TWT request and response frames.

3. A method for channel reservation in a wireless network, characterized in that The steps include: In WLAN, AP or STA reserves the backoff value for the next or next channel access in the PPDU sent. First, each station maintains a "reserved backoff value table". The reserved backoff value table indicates whether the channel is reserved by other stations from the current moment. In the reserved backoff value table, the value of the i-th element is 1, indicating that the i-1th time slot in the future is reserved by other stations; the value of 0 indicates that the i-1th time slot in the future is not reserved by other stations. The values ​​and meanings are opposite, or other storage structures or value methods are used. As long as it can be distinguished whether the i-th time slot in the future is reserved by other stations, the current moment is recorded as the 0th time slot. The time slot refers to: 1) The TXOP time period when the user is a TXOP holder; 2) Physical carrier sensing or virtual carrier sensing determines that the channel is busy until the channel changes from busy to idle for a period of DIFS or AIFS; 3) Physical carrier sensing or virtual carrier sensing determines that the channel is idle and a backoff time slot has passed. Each station deletes the frontmost element in the "reserved backoff value table" every time a time slot has passed, representing that a time slot has passed; The specific steps are: Step 1: The first station sends a first PPDU, which carries channel reservation information; the channel reservation information is the backoff value of the first station immediately following the next channel access, the backoff value of the next channel access represents the backoff value of the next consecutive channel access, and the backoff value of the next or subsequent multiple channel accesses is called the reservation backoff value; The channel reservation information is carried in a MAC frame carried by the first PPDU, or in a preamble of the first PPDU; If the channel reservation information is carried in the MAC frame, the first implementation method is to carry it in the A control field in the IEEE 802.11 standard, where the control identification field uses a value reserved in the IEEE 802.11 standard, and the value indicates that the A control field identifies the channel reservation information; The first implementation of the control information field is that the value of the control information field directly represents the backoff value of a future channel access; The second implementation of the control information field indicates the backoff value of multiple channel accesses in the future. First, the control information field includes a reservation number field, the reservation number field value is the reservation number N, and the reservation number field is followed by a backoff value field, and the backoff value field indicates the backoff value of the next N channel accesses in the future. The third implementation of the control information field indicates the backoff values ​​of multiple channel accesses in the future, including multiple backoff value fields. The value of the i-th backoff value field determines the backoff value of the i-th channel access in the future. The value of the i-th backoff value field is m, and m≥0, which means that the backoff value of the i-th channel access in the future is m. Each backoff value field contains a special value, which means that the backoff value of the i-th channel access in the future is not specified. If the channel reservation information is carried in the preamble of the first PPDU, the position of the channel reservation information in the preamble of the first PPDU is not restricted; The backoff value reserved by the first site cannot be a backoff value of 1 in the "reserved backoff value table"; The first backoff time slot of the first station's i-th backoff is the time slot next to the first station's i-1-th channel access success time slot; Step 2: The second station successfully receives the first PPDU and successfully parses the channel reservation information carried in the first PPDU; Suppose the channel reservation information represents the backoff value of the first station for the next N channel accesses, denoted as o1, o2, ..., oN; The time slot corresponding to the backoff value of the first station's future N channel accesses is filled with 1 in the corresponding position of the "reserved backoff value table" of the second station; specifically, the value of the element o1+1, o1+o2+1, ... o1+o2+...+oN+1 in the "reserved backoff value table" of the second station is set to 1; Step 3: When the backoff value reserved by the first station reaches its own, if there is a packet to be transmitted, one of the decision rules is used to determine whether the PPDU can be sent.

4. A method for channel reservation in a wireless network, characterized in that The steps include: In a WLAN, the AP and non-AP STA exchange channel reservation capabilities and configure channel reservation enabling parameters. The specific steps are as follows: Step 1: The first non-AP STA sends a first management frame to the first AP, where the first management frame indicates whether the first non-AP STA has a channel reservation capability; the first management frame is a probe request frame, an association request frame, or a reassociation request frame; Step 2: The first AP sends a second management frame to the first non-AP STA, where the second management frame indicates whether the AP has the channel reservation capability; the second management frame is a beacon frame, a detection response frame, an association response frame, or a reassociation response frame; The second management frame contains 0, 1 or more of the following information: Channel reservation enable information, indicating whether channel reservation is enabled; a value of 1 indicates that the channel reservation function is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function is enabled, and a value of 2 indicates that the channel reservation function is enabled, and a value of 0 indicates that the channel reservation function is disabled; or a value of 1 indicates that the channel reservation function is enabled, and a value of 2 indicates that the channel reservation function is enabled, and a value of 3 indicates that the channel reservation functions described in Example 1 and Example 2 are enabled at the same time, and a value of 0 indicates that the channel reservation function is disabled.

5. The channel reservation method in a wireless network according to claim 1 or 2, characterized in that: The judgment rules are as follows. If one of them is met, the PPDU can be determined to be sent: 1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately; 2) If NAV is 0 and the carrier sense is continuously idle for a short period of time from the scheduled time, the PPDU is sent immediately; the short period of time is not limited and can be SIFS or PIFS; 3) If normal backoff is successful, PPDU is sent immediately.

6. The method for channel reservation in a wireless network according to claim 3, characterized in that: The judgment rules are as follows, and any one of them will suffice: 1) If NAV is 0 and the current carrier sense is determined to be idle, the PPDU is sent immediately; 2) When the backoff value reserved by the first station reaches its own, if there is no packet transmission, it sends a frame to indicate that there is no packet transmission. For example, the frame is a QoS Null frame in IEEE 802.11, or an NDP frame.

7. A communication device, comprising a unit or module for executing the method according to any one of claims 1 to 6.

8. A computer-readable storage medium, wherein program instructions are stored in the computer-readable storage medium, and when the program instructions are executed on a computer, the computer is caused to execute the method according to any one of claims 1 to 6.

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